The present disclosure relates to a motor drive device, and more particularly to a technology for driving a stepping motor.
In recent years, stepping motors have been used in various fields including information equipment fields. As drive schemes for a stepping motor, known are a clock scheme in which the motor is rotated by a predetermined step angle at edge timing of a clock signal and a parallel scheme in which the motor is rotated based on a combination of a signal indicating the polarity of an exciting current for the motor and a signal indicating the current amount of the exciting current. Recently, the clock scheme is often used because of its advantages that the control is easy and the number of signals is small.
A stepping motor drive device employing the clock scheme is shown in FIG. 19. A pulse generation circuit 60 generates pulses at the timing of rising edges of a clock signal. According to the output of the pulse generation circuit 60, a step position control circuit 61 generates a signal for controlling a motor 63 in an excitation mode corresponding to an excitation mode signal. A motor drive circuit 62 supplies currents to windings 64 and 65 of the motor 63 according to the output of the step position control circuit 61 (see Japanese Patent Publication No. 2006-288056, for example).